Plant-derived nanotherapeutic systems to counter the overgrowing threat of resistant microbes and biofilms

Plant-Derived Vesicles: A New Era for Anti-Cancer Drug Delivery and Cancer Treatment

Lipid-structured vesicles have been applied for drug delivery system for over 50 years. Based on their origin, lipid-structured vesicles are divided into two main categories, namely synthetic lipid vesicles (SLNVEs) and vesicles of mammalian origin (MDVEs). Although SLNVEs can stably transport anti-cancer drugs, their biocompatibility is poor and degradation of exogenous substances is a potential risk. Unlike SLNVEs, MDVEs have excellent biocompatibility but are limited by a lack of stability and a risk of contamination by dangerous pathogens from donor cells. Since the first discovery of plant-derived vesicles (PDVEs) in carrot cell supernatants in 1967, emerging evidence has shown that PDVEs integrate the advantages of both SLNVEs and MDVEs. Notably, 55 years of dedicated research has indicated that PDVEs are an ideal candidate vesicle for drug preparation, transport, and disease treatment. The current review systematically focuses on the role of PDVEs in cancer therapy and in particular compares the properties of PDVEs with those of conventional lipid vesicles, summarizes the preparation methods and quality control of PDVEs, and discusses the application of PDVEs in delivering anti-cancer drugs and their underlying molecular mechanisms for cancer therapy. Finally, the challenges and future perspectives of PDVEs for the development of novel therapeutic strategies against cancer are discussed.

Nanosizing of Lavender, Basil, and Clove Essential Oils into Microemulsions for Enhanced Antioxidant Potential and Antibacterial and Antibiofilm Activities

Plant essential oils (EOs) possess significant bioactivities (antibacterial and antioxidant) and can be substituted for potentially harmful synthetic preservatives in the food industry. However, limited water solubility, bioavailability, volatility, and stability limit their use. Therefore, the goal of this research was nanosizing lavender essential oil (LEO), basil essential oil (BEO), and clove essential oil (CEO) in a microemulsion (ME) to improve their physicochemical attributes and bioefficacy. Tween 80 and Transcutol P were utilized for construction of pseudoternary phase diagrams. It was observed that the concentration of EOs had a great impact on the physicochemical and biological properties of MEs. A spherical droplet of MEs with a diameter of less than 20 nm with a narrower size distribution (polydispersity index (PDI) = 0.10-0.27) and a ζ potential of -0.27 to -9.03 was observed. ME formulations were also evaluated for viscosity, conductivity, and the refractive index. Moreover, the impact of delivery systems on the antibacterial property of EOs was assessed by determining the zone of inhibition and minimum inhibitory concentration against two distinct pathogen classes (S. aureus and E. coli). Crystal violet assay was used to measure the growth and development of biofilms. According to bioefficacy assays, ME demonstrated more efficient antibacterial activity against microorganisms at concentrations lower than pure EOs. CEO ME had superior activity againstS. aureus and E. coli. Similarly, dose-dependent antioxidant capacity was noted for MEs. Consequently, nanosized EO formulations with improved physicochemical properties and enhanced bioactivities can be employed in the food processing sector as a preservation agent.

Curcumin-Loaded Bioactive Polymer Composite Film of PVA/Gelatin/Tannic Acid Downregulates the Pro-inflammatory Cytokines to Expedite Healing of Full-Thickness Wounds

Curcumin (Cur) entrapped poly(vinyl alcohol) (PVA)/gelatin composite films were prepared by cross-linking with tannic acid (TA) as bioactive dressings for rapid wound closure. Films were evaluated for mechanical strength, swelling index, water vapor transmission rate (WVTR), film solubility, and in-vitro drug release studies. SEM revealed uniform and smooth surfaces of blank (PG9) and Cur-loaded composite films (PGC4). PGC4 exhibited excellent mechanical strength (tensile strength (TS) and Young's modulus (YM) were 32.83 and 0.55 MPa, respectively), swelling ability (600-800% at pH 5.4, 7.4, and 9), WVTR (2003 ± 26), and film solubility (27.06 ± 2.0). Sustained release (81%) of the encapsulated payload was also observed for 72 h. The antioxidant activity determined by DPPH free radical scavenging showed that the PGC4 possessed strong % inhibition. The PGC4 formulation displayed higher antibacterial potential against S. aureus (14.55 mm zone of inhibition) and E. coli (13.00 mm zone of inhibition) compared to blank and positive control by the agar well diffusion method. An in-vivo wound healing study was carried out on rats using a full-thickness excisional wound model. Wounds treated with PGC4 showed very rapid healing about 93% in just 10 days post wounding as compared to 82.75% by Cur cream and 80.90% by PG9. Furthermore, histopathological studies showed ordered collagen deposition and angiogenesis along with fibroblast formation. PGC4 also exerted a strong anti-inflammatory effect by downregulating the expression of pro-inflammatory cytokines (TNF-α and IL-6 were lowered by 76% and 68% as compared to the untreated group, respectively). Therefore, Cur-loaded composite films can be an ideal delivery system for effective wound healing.

Oil mediated green synthesis of nano silver in the presence of surfactants for catalytic and food preservation application

The present study details the green synthesis of silver nanoparticles using clove oil as a reducing and stabilizing agent. Cationic, anionic, nonionic and zwitterionic surfactants were introduced to study the change in size, shape, and morphology of nanoparticles. The nanoparticles were characterized using different techniques. The nanoparticles had shown specific surface Plasmon resonance band with absorbance between 380 and 385 nm. The X-ray diffraction study revealed that the nanoparticles are composed of spherical cubic crystals with average size between 136 and 180 nm while Dynamic Laser scattering (DLS) studies revealed an effective diameter of 82 nm and polydispersity index of 0.005. Thermogravimetric analysis suggested that the particles are stable even at 600 °C. All the samples presented good antibacterial and antifungal efficacies against Staphylococcus aureus, Klebsiella pneumonia and Candida albicans and good catalytic activities for the degradation of fast green and Allura red dyes. Further, thin edible films of the nanoparticles were prepared using sodium alginate for food preservation. The films were coated on fruits and vegetables for extending their shelf life to cope with demand and supply gap.